Safety system



May 1 964 J. c. GARRETT SAFETY SYSTEM 2 Sheets-Sheet 1 Filed March 10,1959 1N VENTOR. JOHN 'C. GARRETT 62,4- Juan.

A TTOR/VE Y May 19 1964 J. c. GARRETT SAFETY SYSTEM 2 Sheets-Sheet 2Filed Maxim 10, 1959' g/IIIIIIIIZI:

lllllllli'rlllllll 32 33 mm wlllllllllllliblllll INVENTOR. JOHN C.GARRETT A TTOR/VE Y United States Patent 3,133,667 SAFETY SYSTEM JohnClifiord Garrett, Beverly Hills, Calif., assignor to The GarrettCorporation, Los Angeles, Calif., 21 corporation of California FiledMar. 10, 1959, Ser. No. 798,428 2 Claims. ill. 220-88) This inventionrelates generally to safety means and is more particularly directed to asystem for preventing accidental explosions due toleakage from a fuelsystem or its components.

' A basic safety system embodying the present invention includes meansforming a sealed envelope for enclosing a fuel system and otherassociated apparatus and collecting leakage therefrom, the envelopebeing provided with means for disposing of the fuel leakage in a safemanner. Modifications of the invention may include means for introducingan inert medium into the envelope to combine with the leakage, meansforming an outlet which establishes communication between the interiorand exterior of the envelope, and means operative to regulate the flowof the inert medium containing fuel leakage through such outlet. Meansmay also be provided to consume or burn the fuel in the escaping medium,as it passes from the outlet, to reduce the possibility of an explosionand to salvage the energy in the fuel thus discharged. Since it isimportant to constantly maintain a completely inert atmosphere in theenvelope, a reservoir containing inert matter and means to conduct andregulate flow therefrom into said envelope may be provided, whenappropriate, to replace any loss ofthe inert matter from the envelope.

It is an object of the present invention to provide a safety systemcomprising means forming a sealed envelope for enclosing a fuel systemand collecting fuel leakage therefrom, means being provided inconnection with the envelope to dispose of the leakage before adangerously explosive amount can accumulate.

Another object of this invention is to provide a safety system having acasing for enclosing a fuel system, the

casing being provided with means for supplying the interior thereof withan inert medium, the casing also being provided with an outlet includingan ignition device to permit the controlled discharge and burning of anyfuel which may have leaked from the fuel system and been combined withthe inert medium.

Another object of this invention is to provide a safety device having afuel system disposed in a casing containing an inert medium, the casingbeing formed with an outlet having a flow control mechanism thereinwhereby the outflow of inert fluid and fuel from the interior of thecasing will be regulated according to a predetermined schedule based onthe amount of leakage from the fuel system.

A further object of this invention is to provide a safety device of thetype having a feul system and associated apparatus enclosed in a casingcontaining an inert medium, reservoir means containing inert matterbeing provided to operatively communicate with the interior of thecasing for replacing inert matter according to a predetermined schedulebased on the amount of leakage from said casing.

A further object of the present invention is to provide a safety deviceof the type having a fuel system and an engine disposed in a casing. Inthis device the engine component thereof includes intake and exhaustmeans which communicate with the exterior of said casing, the fuelsystem thereof communicating with the engine via passages contained inthe casing; thus leakage from the fuel system will be confined to thecasing and may then be disposed of by burning in a predetermined saferegion.

Other objects and advantages of the invention will become apparent topersons skilled in the art by reference to the following detaileddescription and accompanying drawings wherein:

FIGURE 1 is a diagrammatic View partly in section showing a safetydevice embodying the present invention applied to a fuel system andassociated engine;

FIG. 2 is a detailed sectional View taken through a portion of thedevice shown in FIG. 1 on the plane in dicated by the line 22 of suchfigure; and

FIGS. 3, 4 and 5 are diagrammatic views illustrating slight variationsof the invention.

Referring more particularly to FIG. I of the drawings, it will be seenthat the safety system forming the subject matter of the invention hasbeen illustrated in one of its many applications. In this figure thesafety system is applied to a power generating unit including a gasturbine engine and its associated fuel system. The engine may serve as agas generator or produce pneumatic or shaft power as required. It is tobe understood at this point that the safety system comprising theinvention may be applied to any type of engine-and fuel system or anycomponents thereof which receive combustible fuel and are apt to leakand create the hazard of an explosion.

The safety system shown in FIG. 1 includes a casing or envelope 1 whichis formed to receive and support a gas turbine, or any other type ofengine, 2 and its associated fuel system designated generally by thenumeral 3.

Fuel system 3 includes a reservoir 4, a pump 5, and piping 6 throughwhich the fuel is drawn from the reservoir and supplied to the engine inthe usual manner. Other necessary or desired fuel system components maybe provided to control the operation of the engine.

The safety system is provided to reduce or eliminate the dangers ofexplosions resulting from leakage of fuel from the reservoir or otherfuel system components. Intake and exhaust passages 7 and 8,respectively, are provided to admit air from the ambient atmosphere tothe engine and conduct gases of combustion therefrom.

Casing 1 is provided to enclose the engine and fuel system and catch anyfuel leaking from the system. To reduce the danger of the leakage thuscollected from combining with air and producing an explosive mixture, itis proposed to charge the envelope 1 with an inert medium, such ashelium. This objective is attained by providing a container 10 of theinert fluid and connecting the outlet of the container with the interiorof the envelope by a line 11. A suitable pressure responsive valve 12 isdisposed in the line 11. After the engine and fuel system are assembledin the envelope 1 and the outlet of the container is opened, valve 12will admit suflicient inert medium to charge the interior of theenvelope to a predetermined pressure above atmospheric pressure topreclude the entrance of air at such pressure. Leakage from thereservoir 4, the pump 5, or any other part of the system will combinewith the inert fluid to preclude, as much as possible, the formation ofan explosive mixture.

As a further protection against explosions, the envelope 1 is providedwith an outlet passage in the form of a tube 13 which extends from asmall dome-shaped vapor trap 14 disposed at the top of the envelope.This trap is so located because of the tendency of lighter gases torise; the trap is in open communication with the interior of the casing.Tube 13 leads to an outlet fitting 15 provided at one side of andcommunicating with the turbine exhaust passage 3. It will be obviousthat as the pressure increases within the envelope, gaseous fluidscontained therein will tend to flow through the tube to the outletfitting and escape to the atmosphere via the exhaust passage 8. Toprevent waste of the inert medium, the outlet fitting may be providedwith a pressure responsive relief valve 16 of any suitable type whichwill be adjusted to prevent flow through tube 13 and outlet fitting 15until a predetermined pressure, above that for which valve 12 has beenset, is reached in the envelope 1. This increase in pressure may becaused by the escape of fuel under a pressure exceeding that of theinert medium in the envelope. When valve 16 opens and a mixture of fuelleakage and inert medium flows into the outlet fitting 15, the mixturewill be discharged into the exhaust gas stream where it will be safelyburned.

Still further protection may be secured by providing the outlet fitting15 with a burner 17 adjacent the downre-am side of the valve 16. Burneror pilotignitor 17 may also be of any suitable type, the one shown inFIG. 1 projecting into the fitting 15 and communicating with a line 18which, in turn, is connected with the fuel system 3. It should beobvious that if it is desired or found necessary to maintain operationof the pilot burner 1'7 when the engine 2 or its fuel system is not inoperation, a separate source of fuel or an electric ignition devicecould be provided without departing from the concept of this invention.To sustain the ignition of fuel supplied to the burner 17, air may beconducted to the burner from the engine plenum through a line 2%. Thus,when a mixture containing fuel issues from the tube 13 through valve 16,the fuel will be ignited by the flame from the burner 17, and safelyburned in the exhaust passage.

To summarize the operation of the safety system shown in FIG. 1 it maybe stated that following the assembly of the engine and fuel system inthe envelope 1, the interior of the latter is purge-d of air, or othercombustion supporting medium, and then charged with inert gas from thecontainer 1% When the pressure for-which valve 12 has been set isreached, the flow of inert gas into the casing 1 will cease. Thereservoir 4 is then filled with the desired fuel and the engine may beoperated. If the fuel system has been properly constructed and remainsin good condition, the safety system will be inoperative. If, however,fuel should leak from the fuel system, the leakage will combine with theinert gas and the formation of a combustible mixture will be prevented.Continued leakage will cause the pressure in the envelope 1 to riseuntil valve 16 opens and permits the combined fuel and inert gas toescape to the exhaust passage 8. The fuel will be burned in the exhaustgases. if the safety system is provided with the pilot burner 17, thefuel in the escaping mixture will be burned regardless of whether anyexhaust gases are flowing from the engine.

While a unitary safety system for protecting an entire engine and fuelsystem has been shown in FIG. 1, it will be apparent that separatesystems could be provided for the various components of a fuel system,such as the fuel storage tank, the pump, the engine, the controls, andother parts. For example, FIGS. 3, 4 and illustrate features of theinvention applied to heat exchangers which may be employed in a fuelsystem. In FIG. 3, the heat exchanger 21 is enclosed in a casing 22 tocollect fuel leakage therefrom. The casing communicates with an inlet 23for a suitable medium and an outlet passage 24. The latter is providedwith an exhaust fan 25 so that the suitable medium may be drawn throughthe inlet 23, swept over the exterior of the heat exchanger 21, andexhausted through the outlet passage 24 to a suitable region whereburning of the fuel may safely be performed.

In PEG. 4, the heat exchanger 25' is also enclosed in a casing 26 whichis provided with an outlet passage 27 only. This passage is alsoprovided with an exhaust fan 28 by which a partial vacuum may bemaintained in the casing 26. If fuel should leak from the heatexchanger,

4 it will be drawn from the casing 26 as fast as it flows in and may beconsumed by the flame of a burner 39 placed in a suitable safe regiondownstream of the fan 28.

FIG. 5 illustrates a heat exchanger 31 enclosed in a casing 32 which isprovided with one or more ignitors 33. The latter elements areconstantly energized and serve to cause the burning of leakage as fastas it occurs, thus preventing the accumulation of a large combustiblemixture which might cause a serious explosion.

The invention has been illustrated in some of its simplest forms, but itshould be understood that the configuration and arrangement of parts maybe Widely varied without departing from the spirit and scope of theinvention, as herein shown and described.

I claim:

1. In a safety device, the combination comprising: means forming asealed envelope for receiving at least a portion of a fuel system andcollecting leakage therefrom; reservoir means for containing an inertmedium under pressure; passage means establishing communication betweensaid reservoir and the interior of said envelope; valve means in saidpassage means responsive to a reduced pressure in said envelope to admitinert medium to said envelope, escape of fuel from the portion of thefuel system therein tending to increase the pressure in said envelope;outlet means leading from the interior of said envelope to the exteriorthereof; valve means in said outlet means responsive to a predeterminedpressure to permit fuel and inert medium mixture to flow from saidenvelope through said outlet means; and burner means in said outletmeans at the downstream side of said valve means to ignite the fuel insaid mixture as the latter passes through said outlet means.

2. In a safety device, the combination comprising: means forming asealed envelope for receiving at least a portion of a fuel system andcollecting leakage therefrom; reservoir means for containing an inertmedium; a localized region formed in said envelope to collect fuelleakage from said portion of the fuel system; passage means establishingcommunication between said reservoir and the interior of said envelope;valve means in said passage means responsive to a reduced pressure insaid envelope to admit inert medium to said envelope, escape of fuelfrom the portion of the fuel system therein tending to increase thepressure in said envelope; outlet means leading from said localizedregion in said envelope to the exterior of said envelope; valve means insaid outlet means responsive to a predetermined pressure to permit fueland inert medium mixture to flow from said envelope through said outletmeans; and burner means in said outlet means at the downstream side ofsaid valve means to ignite the fuel in said mixture as the latter passesthrough said outlet means.

References Cited in the file of this patent UNITED STATES PATENTS1,286,528 Carson Dec. 3, 1918 2,480,230 Elster Aug. 30, 1949 2,881,057Cole Apr. 7, 1959 2,889,955 Naulty et a1. June 9, 1959 2,944,563 DeBlasio et a1. July 12, 1960 FOREIGN PATENTS 150,053 Great Britain Aug.24, 1920 367,579 Great Britain Feb. 25, 1932 554,664 Germany July 14,1932

1. IN A SAFETY DEVICE, THE COMBINATION COMPRISING: MEANS FORMING ASEALED ENVELOPE FOR RECEIVING AT LEAST A PORTION OF A FUEL SYSTEM ANDCOLLECTING LEAKAGE THEREFROM; RESERVOIR MEANS FOR CONTAINING AN INERTMEDIUM UNDER PRESSURE; PASSAGE MEANS ESTABLISHING COMMUNICATION BETWEENSAID RESERVOIR AND THE INTERIOR OF SAID ENVELOPE; VALVE MEANS IN SAIDPASSAGE MEANS RESPONSIVE TO A REDUCED PRESSURE IN SAID ENVELOPE TO ADMITINERT MEDIUM TO SAID ENVELOPE, ESCAPE OF FUEL FROM THE PORTION OF THEFUEL SYSTEM THEREIN TENDING TO INCREASE THE PRESSURE IN SAID ENVELOPE;OUTLET MEANS LEADING FROM THE INTERIOR OF SAID ENVELOPE TO THE EXTERIORTHEREOF; VALVE MEANS IN SAID OUTLET MEANS RESPONSIVE TO A PREDETERMINEDPRESSURE TO PERMIT FUEL AND INERT MEDIUM MIXTURE TO FLOW FROM SAIDENVELOPE THROUGH SAID OUTLET MEANS; AND BURNER MEANS IN SAID OUTLETMEANS AT THE DOWNSTREAM SIDE OF SAID VALVE MEANS TO IGNITE THE FUEL INSAID MIXTURE AS THE LATTER PASSES THROUGH SAID OUTLET MEANS.